BMB Seminar: Justin Hines (Lafayette)

The heritable amyloids of Saccharomyces cerevisiae – Defining prion-specific chaperone functions in yeast

Justin K. Hines, PhD
Associate Professor of Chemistry, Lafayette College

Yeast prions are heritable amyloid aggregates of functional proteins. Their propagation to subsequent cell generations is dependent upon the fragmentation of these aggregates by a core set of chaperone proteins. Three proteins make up the core ‘prion-chaperone machinery’: the J-protein Sis1, the Hsp70 Ssa, and the disaggregase Hsp104, and yet some prions exhibit requirements for additional chaperone activities, indicating that prion-chaperone requirements are heterogeneous. Further, prions can form distinct amyloid structures (amyloid structural polymorphisms), called ‘strains’ in mammalian systems and ‘variants’ in yeast, that dictate the intensity of yeast prion-associated phenotypes and stability in mitosis. Recently we and others have uncovered significant complexity in the chaperone requirements of various yeast prions and prion variants. Two specific examples will be discussed: our recent report of distinct prion- and variant-specific requirements for the Hsp70 co-chaperone Sis1, and the unusual requirement of the atypical J-protein Swa2 by at least one variant of the prion [URE3]. Because J-proteins often act as targeting factors for Hsp70s, they may constitute the first chaperone response to the presence of amyloid, but a critical barrier to advancing the understanding of chaperone function in prion biology is that the fundamental chaperone requirements for most yeast prions remain unidentified, precluding a comprehensive understanding of how protein sequences give rise to amyloids with distinct patterns of chaperone interaction.

Light snacks and drinks will be provided
Sponsored by: EPACC, BMB, Chemistry Department, Biology Department
Questions? Contact Shelli Frey (

Monday, September 9, 2019 at 4:00pm to 5:00pm

Science Center 200

Biology Department
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